The second alien invasion has been going on for two years and guerrilla warfare has taken on new meaning. Their bases pop up randomly like hornet's nests and spawn robotic killing machines designed to wipe humans off the face of the Earth. As commander, you take control of a fleet of Ultrabots from the Ultrabot war room at basecamp and direct cleansing actions on thirteen different missions designed to attack and destroy enemy basecamps while defending and strengthening your own.